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ePoster Display

137P - Trial comparing the safety, efficacy and immunogenicity of trastuzumab biosimilar candidate (TX05) with originator trastuzumab in HER2+ early breast cancer


16 Sep 2021


ePoster Display


Management of Systemic Therapy Toxicities;  Cytotoxic Therapy;  Surgical Oncology;  Supportive Care and Symptom Management

Tumour Site

Breast Cancer


Peter Krivorotko


Annals of Oncology (2021) 32 (suppl_5): S407-S446. 10.1016/annonc/annonc687


P. Krivorotko1, A. Manikhas2, F. Moiseenko3, E. Poddubskaya4, S.P. Neciosup5, M. Gopichand6, D. Osynskyi7, T. Haynes8, J. Lai8, B.J. Mills8

Author affiliations

  • 1 Breast Cancer Department, N.N. Petrov National Medical Research Center of Oncology, 197758 - Saint-Petersburg/RU
  • 2 Breast Department, City Clinical Oncology Dispensary, St. Petersburg/RU
  • 3 Oncology, St. Petersburg Clinical Research and Practical Center for Specialized Types of Medical Care (Oncologic), St. Petersburg/RU
  • 4 Tumor Diagnostics Department, I.M. Sechenov First Moscow State Medical University, 119435 - Moscow/RU
  • 5 Medicine, Instituto Nacional de Enfermedades Neoplasicas, INEN, Lima 34 - Lima/PE
  • 6 Surgical Oncology, City cancer Center, 520002 - Vijayawada/IN
  • 7 Oncology, Kyiv City Clinical Oncological Centre, 3115 - Kiev/UA
  • 8 Tanvex Biopharma Usa, Inc., Tanvex BioPharma USA, Inc., New Taipei/TW


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Abstract 137P


Biosimilars present patients with additional treatment options and may increase access by potentially lowering costs. TX05 is a trastuzumab biosimilar candidate manufactured in the United States. We report results of a phase III study (TX05-03) comparing the efficacy and safety of TX05 to originator trastuzumab (TRA) in patients with HER2+ early breast cancer (EBC).


TX05-03 was a randomized, double-blind, parallel group phase III trial with patients enrolled at 124 centers in 10 countries (Belarus, Ukraine, Russia, Georgia, Hungary, Philippines, Mexico, Chile, Peru and India). Treatment included four 3-week cycles of epirubicin and cyclophosphamide followed by four 3-week cycles of paclitaxel and TX05 or TRA. Definitive surgery was completed 3 to 7 weeks after completion of treatment, and pathologic complete response (pCR) in the per protocol population was defined as the primary study endpoint. Equivalence was concluded if the 95% CI of the risk ratio (TX05/TRA) was contained within the pre-defined interval [0.755, 1.325].Secondary endpoints were objective response rate (ORR), immunogenicity and safety.


Of the 809 subjects randomized, 674 were evaluable for efficacy (TX05=336; TRA=338). Demographic and baseline characteristics were well balanced between the two arms. Based on independent central review, in the per-protocol population, 48.8% of patients achieved pCR in the TX05 arm versus 45.3% in the Herceptin®arm. The pCR risk ratio was 1.0783 (95% CI, 0.9185 to 1.2659), within the predefined equivalence margin. Week 24 ORR was 87.2% for TX05 compared to 87.9% for TRA. The ratio of ORR, 0.9924, was also within the pre-defined equivalence margin (95% CI: 0.9374, 1.0506). Frequency, type and severity of adverse events were similar between TX05 and Herceptin and no new safety signals were detected.


The pCR risk ratio was within the predefined equivalence margins, confirming therapeutic equivalence of TX05 and Herceptin. Secondary endpoints including ORR, safety and immunogenicity were comparable and support the conclusion of biosimilarity.

Clinical trial identification

NCT03556358; EudraCT 2017-004190-13.

Editorial acknowledgement

Legal entity responsible for the study

Tanvex BioPharma USA, Inc.


Tanvex BioPharma USA, Inc.


P. Krivorotko, F. Moiseenko, E. Poddubskaya, S.P. Neciosup, M. Gopichand, D. Osynskyi, T. Haynes, J. Lai, B.J. Mills: Financial Interests, Personal, Invited Speaker: Tanvex BioPharma USA, Inc. A. Manikhas: Financial Interests, Institutional, Invited Speaker: Tanvex BioPharma USA, Inc.

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